JPS6457342A - Malfunction detector for data processor - Google Patents

Abstract

PURPOSE:To improve the efficiency of debugging, by providing the titled device with a search data register for storing specific data, a current data register for sequentially storing data in transfer and a data comparator for detecting the coincidence/discrepancy of outputs from both registers. CONSTITUTION:When data 'A' which should not be written in address '1000' at normal time are written in error, '1000' is set up in a search address register 1 and the 'A' is set up on the search data register 6. On the other hand, 'write operation' and 'data coincidence' are set up in a mode register 4. When the data 'A' are written in address '1000' in error, both of an address comparator 3 and a data comparator 8 output coincidence signals and 'write operation' and 'data coincidence' are set up also in the mode register 4, so that a control circuit 5 regards the state as the detection of address coincidence and outputs a malfunction detecting signal.